Actual source code: ex1e.c
2: /* Program usage: mpiexec ex1 [-help] [all PETSc options] */
4: static char help[] = "Demonstrates various vector routines.\n\n";
6: /*T
7: Concepts: vectors^basic routines;
8: Processors: n
9: T*/
11: /*
13: This uses the PETSc _ error checking routines. Put _ before the PETSc function call
14: and __ after the call (or ___ in a subroutine, not the main program). This is equivalent
15: to using the ... macros
18: Include "petscvec.h" so that we can use vectors. Note that this file
19: automatically includes:
20: petscsys.h - base PETSc routines petscis.h - index sets
21: petscviewer.h - viewers
22: */
23: #define PETSC_UNDERSCORE_CHKERR
25: #include <petscvec.h>
27: #if defined(PETSC_USE_REAL_SINGLE)
28: #define PETSC_EPS 1.e-5
29: #else
30: #define PETSC_EPS 1.e-10
31: #endif
35: int main(int argc,char **argv)
36: {
37: Vec x, y, w; /* vectors */
38: Vec *z; /* array of vectors */
39: PetscReal norm, v, v1, v2;
40: PetscInt n = 20;
41: PetscScalar one = 1.0, two = 2.0, three = 3.0, dots[3], dot;
43: _ PetscInitialize(&argc,&argv,(char*)0,help);___
44: _ PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);___
46: /*
47: Create a vector, specifying only its global dimension.
48: When using VecCreate(), VecSetSizes() and VecSetFromOptions(), the vector format
49: (currently parallel, shared, or sequential) is determined at runtime. Also, the
50: parallel partitioning of the vector is determined by PETSc at runtime.
52: Routines for creating particular vector types directly are:
53: VecCreateSeq() - uniprocessor vector
54: VecCreateMPI() - distributed vector, where the user can
55: determine the parallel partitioning
56: VecCreateShared() - parallel vector that uses shared memory
57: (available only on the SGI); otherwise,
58: is the same as VecCreateMPI()
60: With VecCreate(), VecSetSizes() and VecSetFromOptions() the option -vec_type mpi or
61: -vec_type shared causes the particular type of vector to be formed.
63: */
64: _ VecCreate(PETSC_COMM_WORLD,&x);___
65: _ VecSetSizes(x,PETSC_DECIDE,n);___
66: _ VecSetFromOptions(x);___
68: /*
69: Duplicate some work vectors (of the same format and
70: partitioning as the initial vector).
71: */
72: _ VecDuplicate(x,&y);___
73: _ VecDuplicate(x,&w);___
75: /*
76: Duplicate more work vectors (of the same format and
77: partitioning as the initial vector). Here we duplicate
78: an array of vectors, which is often more convenient than
79: duplicating individual ones.
80: */
81: _ VecDuplicateVecs(x,3,&z);___
83: /*
84: Set the vectors to entries to a constant value.
85: */
86: _ VecSet(x,one);___
87: _ VecSet(y,two);___
88: _ VecSet(z[0],one);___
89: _ VecSet(z[1],two);___
90: _ VecSet(z[2],three);___
92: /*
93: Demonstrate various basic vector routines.
94: */
95: _ VecDot(x,x,&dot);___
96: _ VecMDot(x,3,z,dots);___
98: /*
99: Note: If using a complex numbers version of PETSc, then
100: PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
101: (when using real numbers) it is undefined.
102: */
103: #if defined(PETSC_USE_COMPLEX)
104: _ PetscPrintf(PETSC_COMM_WORLD,"Vector length %D\n", (int) (PetscRealPart(dot)));___
105: _ PetscPrintf(PETSC_COMM_WORLD,"Vector length %D %D %D\n",(PetscInt)PetscRealPart(dots[0]),
106: (PetscInt)PetscRealPart(dots[1]),(PetscInt)PetscRealPart(dots[2]));___
107: #else
108: _ PetscPrintf(PETSC_COMM_WORLD,"Vector length %D\n",(PetscInt) dot);___
109: _ PetscPrintf(PETSC_COMM_WORLD,"Vector length %D %D %D\n",(PetscInt)dots[0],
110: (PetscInt)dots[1],(PetscInt)dots[2]);___
111: #endif
113: _ PetscPrintf(PETSC_COMM_WORLD,"All other values should be near zero\n");___
115: _ VecScale(x,two);___
116: _ VecNorm(x,NORM_2,&norm);___
117: v = norm-2.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
118: _ PetscPrintf(PETSC_COMM_WORLD,"VecScale %G\n",v);___
120: _ VecCopy(x,w);___
121: _ VecNorm(w,NORM_2,&norm);___
122: v = norm-2.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
123: _ PetscPrintf(PETSC_COMM_WORLD,"VecCopy %G\n",v);___
125: _ VecAXPY(y,three,x);___
126: _ VecNorm(y,NORM_2,&norm);___
127: v = norm-8.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
128: _ PetscPrintf(PETSC_COMM_WORLD,"VecAXPY %G\n",v);___
130: _ VecAYPX(y,two,x);___
131: _ VecNorm(y,NORM_2,&norm);___
132: v = norm-18.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
133: _ PetscPrintf(PETSC_COMM_WORLD,"VecAYPX %G\n",v);___
135: _ VecSwap(x,y);___
136: _ VecNorm(y,NORM_2,&norm);___
137: v = norm-2.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
138: _ PetscPrintf(PETSC_COMM_WORLD,"VecSwap %G\n",v);___
139: _ VecNorm(x,NORM_2,&norm);___
140: v = norm-18.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
141: _ PetscPrintf(PETSC_COMM_WORLD,"VecSwap %G\n",v);___
143: _ VecWAXPY(w,two,x,y);___
144: _ VecNorm(w,NORM_2,&norm);___
145: v = norm-38.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
146: _ PetscPrintf(PETSC_COMM_WORLD,"VecWAXPY %G\n",v);___
148: _ VecPointwiseMult(w,y,x);___
149: _ VecNorm(w,NORM_2,&norm);___
150: v = norm-36.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
151: _ PetscPrintf(PETSC_COMM_WORLD,"VecPointwiseMult %G\n",v);___
153: _ VecPointwiseDivide(w,x,y);___
154: _ VecNorm(w,NORM_2,&norm);___
155: v = norm-9.0*sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
156: _ PetscPrintf(PETSC_COMM_WORLD,"VecPointwiseDivide %G\n",v);___
158: dots[0] = one;
159: dots[1] = three;
160: dots[2] = two;
161: _ VecSet(x,one);___
162: _ VecMAXPY(x,3,dots,z);___
163: _ VecNorm(z[0],NORM_2,&norm);___
164: v = norm-sqrt((PetscReal) n); if (v > -PETSC_EPS && v < PETSC_EPS) v = 0.0;
165: _ VecNorm(z[1],NORM_2,&norm);___
166: v1 = norm-2.0*sqrt((PetscReal) n); if (v1 > -PETSC_EPS && v1 < PETSC_EPS) v1 = 0.0;
167: _ VecNorm(z[2],NORM_2,&norm);___
168: v2 = norm-3.0*sqrt((PetscReal) n); if (v2 > -PETSC_EPS && v2 < PETSC_EPS) v2 = 0.0;
169: _ PetscPrintf(PETSC_COMM_WORLD,"VecMAXPY %G %G %G \n",v,v1,v2);___
172: /*
173: Free work space. All PETSc objects should be destroyed when they
174: are no longer needed.
175: */
176: _ VecDestroy(&x);___
177: _ VecDestroy(&y);___
178: _ VecDestroy(&w);___
179: _ VecDestroyVecs(3,&z);___
180: _ PetscFinalize();___
181: return 0;
182: }
183: